Risk Factors for Gambling Disorder: A Systematic Review

Gambling disorder is a common and problematic behavioral disorder associated with depression, substance abuse, domestic violence, bankruptcy, and high suicide rates. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), pathological gambling was renamed “gambling disorder” and moved to the Substance-Related and Addiction Disorders chapter to acknowledge that research suggests that pathological gambling and alcohol and drug addiction are related. Therefore, this paper provides a systematic review of risk factors for gambling disorder. Systematic searches of EBSCO, PubMed, and Web of Science identified 33 records that met study inclusion criteria. A revised study acknowledges as risk factors for developing/maintaining a gambling disorder being a single young male, or married for less than 5 years, living alone, having a poor education, and struggling financially.


Search Strategy
Studies were identified through search on EBSCO, PubMed, and Web of Science. The reference lists of the selected studies were also reviewed to identify other relevant studies (manual searching). The search equation in EBSCO was: TI (gambling).
AND TI ("contributing factor*" OR predictor* OR caus* OR vulnerabilit* OR outcome* OR chang* OR barrier* OR risk OR seek* OR treatment*). In Pubmed: (gambling [Title] (TI = (gambling)). AND TI=("contributing factor*" OR predictor* OR caus* OR vulnerabilit* OR outcome* OR chang* OR barrier* OR risk OR seek* OR treatment*). The search was limited from the year 2016 and linguistic factors (Portuguese, English, Spanish, or French).

Study Selection
We had four inclusion criteria and built four corresponding exclusion criteria in response. We wanted population over 18 years old, so we excluded children and teenagers. We wanted only empirical studies, so we excluded all case studies, book chapters, theoretical essays, and systematic reviews (with or without meta-analyses). We only wanted studies involving problem or pathological gambling, so we excluded studies that did not include either of those two. Also, we wanted studies involving risk factors associated with gambling problems, so we excluded studies that did not include it. And we only wanted studies published in the last 6 years (since 2016), so we excluded the others.
The studies were selected by two independent reviewers (DM and AA), based on their titles and abstracts, according to recommendations of PRISMA guidelines (Moher et al., 2009).
The agreement index in the study selection process was assessed with Cohen's Kappa and revealed almost perfect agreement, K = 0.98, p < 0.001 (Landis & Koch, 1977). The disagreements among reviewers were discussed and resolved by consensus.

Identification and Screening
Our database searches have retrieved 1,294 studies published between 2016 and 2023. After removing duplicates, the search outcome was reduced to to 629 unique studies. Afterwards, we examined the abstracts and excluded another 498 articles based on wrong publication type (n = 73), wrong theme (n = 335), wrong population (n = 72), or wrong outcome variable (n = 18). After full text analysis, 105 articles were eliminated, based the following criteria: wrong publication type (n = 13), wrong theme (n = 8), wrong population (n = 27), wrong outcome variable (n = 57) (Fig. 1). A total of 33 articles were included (seven from manual searching and 26 from the three databases). The objectives, sample (N, age, % male), and conclusions were extracted from each study.
Records screened by eligibility (n = 131) Records excluded by title for being duplicates (n = 665) Records excluded (n = 498): . Wrong publication type (n = 73); . Wrong theme (n = 335); . Wrong population (n = 72); . Wrong outcome (n = 18).  The most severe GD traits were associated with single and multiple gambling preferences for non-strategic and strategic games, early gambling activity, higher impulsivity, higher dysfunctional scores for the harm avoidance and self-regulation personality traits, and more lifetime stressful life events Kim et al. (2016) Research had three aims; (a) explore gender differences (e.g., demographics, co-morbidities, gambling variables) among helpline callers using psychometrically robust measures, (b) assess whether gender predicts treatment utilization following contact and (c) assess whether systematic gender differences exist on gambling and psychosocial outcomes at 3-, 6-and 12-month follow-ups 43 Women compared to men described greater problem severity and shorter problem duration and were more likely to report video game machines as their most problematic form of gambling, greater distress, and lower quality of life Men, despite the lower severity and distress of the problem, were more likely to access treatment after contacting the helpline An association between altered online gambling participation during COVID-19 and increased mental health problems, increased gambling problem severity, negative impact on household income, and a more financially oriented self-concept  (Browne et al., 2019;Hing & Russell, 2020). However, another study found that troublesome gambling and several of its mental health correlates-depression, anxiety, and stresswere not associated with troubling video game use (Biegun et al., 2020). Regarding psychological risk factors, impulsivity was a significant risk factor (Browne et al., 2019;Dufour et al., 2019;Flórez et al., 2016;Gori et al., 2021;Jiménez-Murcia et al., 2020), demonstrating that active gamblers have more cognitive impulsivity and explicit gambling cognition than inactive gamblers. Also, Wong et al. (2017) found that negative psychological states (i.e., stress) significantly moderated the relationship between gambling cognitions and gambling severity. Participants who reported a higher level of stress had more stable and serious gambling problems than those who reported a lower level of stress, regardless of their level of gambling-related cognitions (Black & Allen, 2021;Jiménez-Murcia et al., 2020;Wong et al., 2017). Pathological gambling risk was positively correlated with dissociative experiences: depersonalization and derealization, absorption and imaginative involvement, and passive influence (De Pasquale et al., 2018). Also, alexithymia increases the risk of developing a gambling disorder (Bibby & Ross, 2017;Gori et al., 2021), and mediates the association between insecure attachment and dissociation (Gori et al., 2021). The results show a clear difference for the loss-chasing behavior (Bibby & Ross, 2017).
The analysis of gambling characteristics identified three distinct clinical traits of the gamblers: early and short-term onset (EOSC) (group 1), early and long-term onset (EOLC) (group 2), and late and short-term onset (LOSC) (Group 3) (Landreat et al., 2020). The incidence of gambling problems and the severity of gambling were higher in the EOSC group than in the other two groups. However, the onset age does not explain the gambling trajectories alone: the two clusters associated with the early onset age showed two distinct gambling trajectories, either a short-term evolution (~ 10 years) or a long-term evolution of the cluster. EOSC (~ 23 years) for the EOLC cluster. The EOLC cluster has a long history of gambling (35.4 years), they spend most money on gambling, with only 53.6% stopping gambling for at least a month. This cluster has a significantly higher preference for online gambling than other clusters. Although EOLC gamblers lived with their partners in most of the cases, they reported the lowest levels of family and social support related to gambling problems. An important feature was the absence of premorbid features of lifelong psychopathology before the onset of gambling problems. Most of LOSC gamblers preferred "pure" gambling (here understood as mere games of chance, as opposed to games that combine skill and chance). Women constituted the majority of the LOSC cluster, where game trajectories were the shortest observed in the study (Landreat et al., 2020).
Pathological gambling increases with the frequency (Cavalera et al., 2017;Hing et al., 2016b;Hing & Russell, 2020) and the diversity of the games (Cavalera et al., 2017;Jiménez-Murcia et al., 2020). Pathological gamblers engaged in a higher range of games of chance, and showed more impulsive responses towards gambling opportunities, including betting on live action games, individual bets, electronic gaming machines, scratch cards or bingo, table games, racing, sports or lotteries and winning non-social games (Hing et al., 2016a).
Furthermore, the main proximal predictors for high-risk gambling in electronic gaming machines (EGM) are higher desires, higher levels of misperceptions, higher session spend, longer sessions, separate EGM games, and EGM games in more locations (Hing & Russell, 2020). Normative influences from media advertising and significant others were also associated with a higher risk of problem gambling (Hing et al., 2016b).
A study that analyzed risk factors in online gaming concluded that more frequent gambling in online EGMs, substance use while gambling, and greater psychological distress were more frequent risk factors. Specifically, in an online sports betting group and an online racing betting group, researchers found that participants were mostly male, young, spoke a language other than English, were under greater psychological stress and showed more negative attitudes towards the game (Hing et al., 2017). However, sports betting gamblers had financial difficulties, while risk factors for online race betting gamblers included betting more often on races, engaging in more forms of gambling, self-reporting as a semiprofessional/professional gambler, and used illicit drugs during the game (Hing et al., 2017).
Furthermore, moderate/highly severe gamblers were more likely to have a poor diet, engaged less in physical activities and had a poor general health than gamblers without problems. Also, tobacco use is associated with low and moderate/highly severe gambling. Low-severity gambling, opposing to moderate/highly severe gambling, was significantly associated with binge drinking and increased alcohol consumption. Unhealthy behaviors did tend to group together, and there was a scaled relationship between the severity of gambling problems and the likelihood of reporting at least two unhealthy behaviors. Compared to problem-free gamblers, low-severity gamblers were approximately twice as likely to have low mental well-being, and moderate/high-severity players were three times more likely to have low mental well-being (Butler et al., 2019).
To identify gambling trajectories in poker players, a latent class growth analysis was carried out over three years. Three gambling problem trajectories were identified, comprising a decreasing trajectory (1st: non-problematic-diminutive), a stable trajectory (2nd: low-risk-stable), and an increasing trajectory (3rd: problematic gamblers-increasing). The Internet as the main form of poker and the number of games played were associated with risk trajectories. Depression symptoms were significant predictors of the third trajectory, while impulsivity predicted the second trajectory. This study shows that the risk remains low over the years for most poker players. However, vulnerable poker players at the start of the study remain on a problematic growing trajectory (Dufour et al., 2019).
Regarding gender differentiation, studies have shown differences between the empirical groupings of men and women on different sociodemographic and clinical measures. In men, the number of DSM-5 criteria for disordered gambling (DG) reached the highest relative importance. This was followed by the degree of cognitive bias and the number of gambling activities. In women, the number of gambling activities reached the highest relative importance for grouping, followed by the number of DSM-5 criteria for PG. The relevance of the grouping was achieved by the cognitive bias .
Women showed a preference for easy bets (easy bets are considered safer, therefore, with a greater chance of winning), electronic gambling machines, scratch cards or bingo for reasons other than socializing, earning money, or for general entertainment (Hing et al., 2016a). Women also reported greater problem severity and shorter problem duration, greater pain, and lower quality of life than men (Delfabbro et al., 2017;Kim et al., 2016). Men prefer to bet on EGMs, table games, races, sports, or lotteries and win non-social games (Hing et al., 2016a), and were more likely to exhibit aggressive behavior towards gaming equipment (Delfabbro et al., 2017). Men differed more between problem gamblers and non-problem gamblers, either through signs of emotional distress or trying to hide their presence in the game room from others. Among women, signs of anger, decreased care and attempts to obtain credit were the most prominent indicators (Delfabbro et al., 2017).
The risk of developing pathological gambling was higher for men with less education and less adaptive psychorelational skills. On the other hand, women with higher levels of education and more adapted psychorelational functioning were more likely to become pathological gamblers. Notwithstanding, the odds of being a pathological non-gambler (anything other than a pathological gambler) were higher for women with a high educational level and more adaptive psychorelational functioning (Cunha et al., 2017).

Risk Factors for Increased Online Gambling During COVID-19
During 2020/21 almost one-quarter of online gamblers increased their gambling during lockdown (Bellringer & Garrett, 2021;Fluharty et al., 2022;Swanton et al., 2021), with this most likely to be on overseas gambling sites, instant scratch card gambling and Lotto (Bellringer & Garrett, 2021;Price et al., 2022). The sociodemographic risk factor for increased online gambling was higher education (Bellringer & Garrett, 2021), or low education (Fluharty et al., 2022), and financial difficulties related to COVID (Price et al., 2022;Swanton et al., 2021).
The studies indicate a link between change in online gambling involvement during COVID-19 and increased mental health problems (Price et al., 2022), including stress from boredom (Fluharty et al., 2022), and higher levels of depression and anxiety (Fluharty et al., 2022;Price et al., 2022).
Behavioral risk factors included being a current low risk/moderate risk/problem gambler, a previously hazardous alcohol drinker (i.e., excessive) or past participation in freeto-play gambling-type games (Bellringer & Garrett, 2021), and alcohol consumption (Fluharty et al., 2022;Swanton et al., 2021). Financial well-being showed strong negative associations with problem gambling and psychological distress (Swanton et al., 2021).
As lockdown restrictions eased, ethnic minority individuals who were current smokers and were less educated were more likely to continue gambling more than usual (Fluharty et al., 2022).

Discussion
With this systematic review, we aimed at exploring what are the risk factors for the development/maintenance of gambling disorder. We also searched the literature for information on differences between pre-pandemic gambling patterns and gambling patterns today. A total of 33 studies examined risk factors associated with gambling problems in adults.
Studies, with mixed samples, have shown several risk factors associated with risk problems for problem or pathological gamblers, namely being male, young, single or married less than 5 years, living alone, having a low level of education, and having financial difficulties.
As for relationships, pathological gamblers have greater difficulties in family and social relationships than non-players (Cowlishaw et al., 2016;Landreat et al., 2020). And they even increase the risk of gambling when they grew up with a single parent (Buth et al., 2017) or parents with addiction problems (Buth et al., 2017;Cavalera et al., 2017;Hing et al., 2017).
As for the type of game, gamblers who played more than one game, and had longer gambling sessions, were at greater risk of problem gambling (Cavalera et al., 2017;Hing et al., 2016a;Hing & Russell, 2020;Jiménez-Murcia et al., 2020).
However, two studies presented different data (Biegun et al., 2020;Çakıcı et al., 2015). Biegun et al. (2020), did not find an association between problem gambling and various mental health correlates, such as depression, anxiety, and stress. In another study, players had higher levels of education and were employed, contrary to data found so far. However, it is necessary to bear in mind that the study was developed in Cyprus and, as the authors themselves mention, it is a country with sociocultural characteristics, such as a history of colonization, socioeconomic problems, and high unemployment (Çakıcı et al., 2015), which may justify that only people with income can become addicted to gambling.
With the COVID-19 pandemic, online gamblers have increased their gambling (Bellringer & Garrett, 2021), aggravating the psychological and social consequences for people with problematic gambling behaviors (Håkansson et al., 2020;Yayha & Khawaja, 2020). The authors highlighted the removal of protective factors, including structured daily life (Yayha & Khawaja, 2020), boredom (Fluharty et al., 2022;Lindner et al., 2020), depression and anxiety (Fluharty et al., 2022), as well a financial deprivation (Price, 2020;Swanton et al., 2021), as the main reasons for the increase in gambling problems during the COVID-19 pandemic. It is well known that the daily lives of many people have been substantially altered, with a high degree of homeschooling for school children and students (Tejedor et al., 2021), also with likely negative effects for young people and their families (Thorell et al., 2021). Likewise, restrictions related to COVID-19 and changes in the lives of many people have led to significant job insecurity, unemployment, and financial problems, as well as fear of illness and mortality, which has increased emotional distress (Shakil et al., 2021;Swanton et al., 2021). Researchers have expressed concerns that COVID-19 would have consequences for the mental health Zheng et al., 2021), as well as substance use disorders, and it is important to adapt treatment during the pandemic. (Marsden et al., 2020). The increase in the incidence and prevalence of behavioral addictions and the relevance of the early onset of the problem of gambling disorder, with its serious consequences, make it necessary to better understand these problems to develop and adapt prevention and treatment programs to the specific needs of according to sex and age. Furthermore, understanding gender-related differences is of great importance in treating behavioral addictions.
The growing availability of gambling in recent decades, a low social knowledge about gambling disorders, and a perception of gambling more in terms of moral weakness than a psychological/psychiatric disorder have an impact on the social acceptance of gambling behaviors (e.g., Hing et al., 2015;Petry & Blanco, 2013;St-Pierre et al., 2014).
This systematic review presents limitations. As in all systematic reviews, there is the risk of reporting bias. As only studies published in identifiable sources were included, unpublished studies may be more likely to not have significant results, thus indicating the absence of risk factors in the involvement in problematic or pathological gambling that we have analyzed. For this reason, we had no constraints regarding geographic and linguistic criteria. Also, the adherence to the PRISMA guidelines, including definition of accurate inclusion and exclusion criteria, the use of independent reviewers, as well as the efforts to diminish publication bias, strengthen this systematic review and better elucidate about risk factors in the involvement in problematic or pathological gambling. Another limitation of this study is the little literature on the post-COVID pathological gambling, which does not allow us to draw conclusions from comparisons. Future research would benefit from making comparisons, not just across gender, but also across culture. Researchers should further explore and understand how cultural environments influence the development of problematic gambling.
Treatment providers must consider the specificities of people with gambling disorders. Therefore, a strong educational/training background for therapists and other professionals, considering the problem of gambling disorders in the diagnosis, a better adaptation of the contents of therapeutic programs, and the creation of materials used in therapy adapted to the patient's needs, would be very much advisable. It would also be helpful to establish therapeutic groups, ideally with at least a couple of patients with gambling disorders.
Funding Open access funding provided by FCT|FCCN (b-on).

Conflict of interest
The authors declare that they have no conflict of interest.
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